This invention generally pertains to railroad car couplers. More specifically, the present invention relates to the tail portion of a coupler knuckle wherein the internal coring has been relocated and/or reconfigured to reduce stresses imposed thereon during use.
The invention is particularly applicable to standard Association of American Railroads (AAR) type E and type F or other knuckle type couplers which are comprised of a coupler head having a vertical lock chamber and a pivotally connected coupler knuckle. However, it will be appreciated by those skilled in the art that the invention has broader applications and may also be adapted to use in other types of railway couplers.
Heretofore, standard type E and type F railway coupler knuckles have been internally cored and have included a core support aperture extending through a surface of the knuckle tail portion. Since the knuckles are frequently carried manually by maintenance personnel for service replacement and the like, they require internal coring for maintaining their weight, approximately 84 pounds at present, within acceptable limits. As can be appreciated, this weight is quite substantial and cannot be increased by much before a knuckle becomes too heavy to be carried and manipulated manually.
Since each knuckle is cored, an aperture located in the tail portion rear wall is required for supporting a core member externally of the knuckle to assure proper placement thereof during the casting process. This aperture also is required to facilitate proper cleaning of the casting sand from the knuckle. Finally, conventional foundry practice advises against having a solid tail portion since such a construction would be more likely to develop internal voids which may weaken the knuckle. This situation is particularly troublesome when the voids approach the knuckle surface in critical areas thereof.
The conventional coupler knuckle construction which is provided with a core support aperture in the rear surface of the tail portion has been found to have certain disadvantages. There is a certain amount of preliminary wearing off of high spots and surface roughness on all bearing surfaces when a coupler initially is placed into service and during the time when the coupler components are becoming seated in place. This seating in place is accompanied by an opening or stretching of the coupler contours. The conventional locations of the tail core support aperture and tail core allow undesired deformation at either one or both of upper and lower pulling lugs during loading which occurs in normal coupler use. Such deformation places a major portion of the coupler pulling forces on the tail portion locking face and causes high localized stresses to be exerted at critical locations. These stresses, in turn, lead to premature fatigue failure of the knuckle.
It has, therefore, been considered desirable to develop an improved coupler knuckle wherein the tail core support aperture and tail core would be repositioned and/or reconfigured to enhance knuckle reliability and service life while retaining the benefits and advantages provided by coring. The subject invention is deemed to overcome the foregoing difficulties and others, and meet the above stated needs while providing better and more advantageous overall results.